As far as I know that is a direct signal straight from the hard drive itself, which is also directed to an LED when you have a drive installed in a removable tray. This might be an oversimplification since signals from multiple drives are combined and routed by the controller to the motherboard pin.
So, if you follow midnight_matt's lead, you can argue it is a driver issue of sorts, caused by the Intel Rapid Storage Technology thing that for some reason is polling the CD/DVD drive constantly.
"When you don't know what you're doing it's best to do it quickly" - Jase #DuckDynasty
I'm pretty sure the issue was coming from Win 8. Here's how I know:
I discovered that Win 8 was not seeing my DVD drive. So I found a fix for that on MSDN that involved adding a registry key and rebooting.
Voila! Not only did Win 8 start seeing my DVD drive, but the hard drive light was back to normal!
The difficult we do right away...
...the impossible takes slightly longer.
I've heard the "snappier" from other people as well... but I guess I'll make the change when I have to. I mostly develop for govt customers and it takes them forever to change as well so I usually want to work in whatever environment most of them are on.